If you've ever tried to use Test::NoWarnings to confirm there are
no warnings generated by your tests, combined with the convenience
of done_testing to not have to declare a test count, you'll have
discovered that these two features do not play well together, as
the test count will be calculated before the warnings test is run,
resulting in a TAP error. (See examples/test_nowarnings.pl in this
distribution for a demonstration.)

This module is intended to be used as a drop-in replacement for
Test::NoWarnings: it also adds an extra test, but runs this test
before done_testing calculates the test count, rather than after.
It does this by hooking into done_testing as well as via an END
block. You can declare a plan, or not, and things will still Just
Work.
